Smartphones and other portable electronic devices typically include multiple antennas for transmitting and receiving data. For instance, smartphones often include a primary antenna that serves as the primary means for transmitting and receiving cellular data and a secondary antenna that allows for the transmission and/or receipt of cellular data in a diversity or a MIMO system and may also serve as the antenna for the receipt and/or transmission of other data, such as GPS data and/or data transmitted via Bluetooth. Based on design and space considerations, the primary and second antennas are often positioned at differing locations within the device housing, such as by being located at or along opposed sides of the device. As a result, the performance of each antenna may be impacted differently based on whether a user grasps the device with his/her left hand or right hand.